The inherent higher specific energy (Wh/g) of fuel cells as compared with batteries, can serve the power demand of next generation vehicle applications. Hydrogen fuel cells can provide higher specific energy (Wh/g), power density (W/L) and double conversion efficiency as compared to batteries, provided that a practical, high density hydrogen storage method is available. Among various alternatives, chemical methods of hydrogen storage provide high specific energy at relatively simple storage conditions.
Ammonia borane (NH3BH3 or “AB”) is a promising hydrogen storage material for fuel cell based vehicle applications and portable electronic devices as it contains 19.6 wt % hydrogen. Current methods of releasing hydrogen from AB include thermolysis and catalytic hydrolysis. Due to limited AB solubility in water, catalytic hydrolysis provides low theoretical H2 yield (˜5.6 wt %) and it also requires expensive catalysts such as ruthenium. Thermolysis, on the other hand, requires an external heating source to provide relatively high temperature (˜170° C.) to release two moles of hydrogen per mol of AB, while the third H2 mole requires even higher temperature (˜500° C.).
Thus, the current methods of releasing hydrogen from AB include relatively high temperatures required, environmental issues, catalyst requirements, high costs, and fluidic management. Accordingly, there is a need for a more efficient method of releasing hydrogen from AB.